Energy storage capacitor device and state monitoring circuit

Abstract

A state monitoring circuit is disclosed for monitoring health states of N energy storage capacitors in an energy-storage capacitor device, the energy-storage capacitor device including N channels, and each channel comprising one energy storage capacitor, where the state monitoring circuit is configured to: disconnect first terminals of the N energy storage capacitors from the energy-storage capacitor device one by one; and determine whether each of the N energy storage capacitors is abnormal in accordance with a voltage at the first terminal of a corresponding one of the energy storage capacitors, where N is a positive integer.

What is claimed is: 
     
       1. A state monitoring circuit for monitoring health states of N energy storage capacitors in an energy-storage capacitor device, the energy-storage capacitor device comprising N channels, and each channel comprising one energy storage capacitor, wherein the state monitoring circuit is configured to:
 a) disconnect first terminals of the N energy storage capacitors from the energy-storage capacitor device one by one; 
 b) determine whether each of the N energy storage capacitors is abnormal in accordance with a voltage at the first terminal of a corresponding one of the energy storage capacitors, wherein N is a positive integer; 
 c) wherein each of the N channels is cut off for a predetermined time, and the predetermined time is greater than a charging time for the energy storage capacitor to be charged to a first threshold with a maximum leakage current; 
 d) wherein during the predetermined time, when the voltage at the first terminal of the corresponding one of the energy storage capacitors is greater than the first threshold, the corresponding one of the energy storage capacitors is determined to be abnormal; and 
 e) wherein the first threshold is determined by a capacitance value of the energy storage capacitor, the predetermined time, and the maximum leakage current of the energy storage capacitor. 
 
     
     
       2. The state monitoring circuit of  claim 1 , wherein the first terminal of each of the N energy storage capacitor is coupled to a reference ground through a switch. 
     
     
       3. The state monitoring circuit of  claim 2 , wherein the state monitoring circuit is configured to control a corresponding switch to be turned off so as to disconnect a corresponding one of the first terminals of N energy storage capacitors from the energy-storage capacitor device. 
     
     
       4. The state monitoring circuit of  claim 1 , wherein when the energy storage capacitor in a corresponding one of channels is determined to be in an abnormal state, the corresponding one of channels continues to be cut off. 
     
     
       5. An energy-storage capacitor device, comprising the state monitoring circuit of the  claim 1 , and further comprising N switches that are each coupled between a corresponding one of the energy storage capacitors and a reference ground, wherein N is a positive integer. 
     
     
       6. The energy-storage capacitor device of  claim 5 , wherein the N switches are configured to be located in the state monitoring circuit. 
     
     
       7. The energy-storage capacitor device of  claim 6 , further comprising a power management circuit configured to:
 a) charge the N energy storage capacitors through an input voltage when the energy-storage capacitor device is powered; and 
 b) provide power stored in the N energy storage capacitors to a power terminal of the input voltage when the energy-storage capacitor device is powered off. 
 
     
     
       8. A state monitoring circuit for monitoring health states of N energy storage capacitors in an energy-storage capacitor device, the energy-storage capacitor device comprising N channels, and each channel comprising one energy storage capacitor, wherein the state monitoring circuit is configured to:
 a) disconnect first terminals of the N energy storage capacitors from the energy-storage capacitor device one by one; 
 b) determine whether each of the N energy storage capacitors is abnormal in accordance with a voltage at the first terminal of a corresponding one of the energy storage capacitors, wherein N is a positive integer; 
 c) wherein each of the N channels is cut off for a predetermined time, and the predetermined time is greater than a charging time for the energy storage capacitor to be charged to a first threshold with a maximum leakage current; 
 d) wherein during the predetermined time, when the voltage at the first terminal of the corresponding one of the energy storage capacitors is greater than the first threshold, the corresponding one of the energy storage capacitors is determined to be abnormal; and 
 e) wherein during the predetermined time, a current flowing through a corresponding one of N energy storage capacitors is obtained to perform current limiting control.